Grocery store display cases are generally used for the display of perishable items such as cut floral, meats and deli products, fruits or vegetables or other produce, or similar items typically requiring circulated air, typically circulated refrigerated air, to maintain the freshness and appearance of the displayed items for sale. The design of most grocery store display cases includes a lower drain trough that collects waste liquid runoff and debris. Air circulating fans and refrigeration coils are generally incorporated within this lower drain trough portion of the display case. The return intake airflow is generally located in front inner portion of the case. The circulated air is drawn down through this front inner portion of the case and flows directly over the drain trough by the air movement refrigeration fans which divert the air through the refrigeration coils. After passing through the refrigeration coils the air is then pushed up the back of the case and exits out the air vents and/or out the case canopy on top discharge models.
The drain trough area is where bacteria, mold, yeast spores, and so forth tend to collect and grow. Documented studies have shown airborne bacteria to be at higher levels in display cases where the air flows directly over the drain trough. The contaminated air in these display cases is recirculated and released directly onto the perishable products (fresh produce, meats, seafood, deli, cut floral, and so forth) shortening the shelf life of the products. Furthermore, the bacteria contaminated air is dispersed outward over the displayed product where there is likely to be contact with consumers and store employees. This creates conditions likely to promote the spread of harmful bacteria, viruses, and so on.
Similar problems exist with frozen product display cases, refrigerated beverage cases, or any display case where circulated or recirculated air may become contaminated. The contaminated air may then contaminate the displayed product and such product contamination and dispersion of harmful bacteria and so forth can contribute to the spread of disease or other health issues.
Another concern involves the ripening gas (ethylene) produced naturally from specific fruits and floral. The ripening gas produced from the products displayed in the display case is released into the air stream, captured in the refrigeration air stream and recirculated repeatedly over the product. As the gas is trapped in the air current, ethylene levels tend to increase which in turn speeds up the ripening process and thereby shortening the self life of the products displayed.
Yet another problem involves the downtime associated with the cleaning and maintaining the display cases. In order to clean and sanitize the cases, all products must be removed from the display racks. Sales are lost during this process since the cleaning process takes a substantial amount of time and generally cannot be completed when the store is closed. The majority of grocery retail stores are open nearly 24 hours per day or from very early in the morning until very late in the evening. The cleaning process is very labor intensive and additional man-hours are required, effecting net profits. Consequently, the frequency of cleaning and maintaining the display cases is minimized, further contributing to the build up of harmful bacteria, microorganisms, and so forth within the display cases.
Prior attempts to address the issue of case contamination include a device that automatically rinses the case's drip pans with water and a chemical solution. The dispensing plumbing pipe is mounted on the back panel of the internal case located directly under the product shelf racks. Spray nozzles are spaced evenly for the entire length of the case. The rinse system is cycled periodically during the day.
This technology only addresses the drip pan surface and does not address several other issues including the contaminated surfaces found below the drip pans. Furthermore, the rinse system does not contemplate and integrate methods and apparatus for effectively addressing airborne contamination within the display case.
The lower trough section of display cases typically includes refrigeration plumbing, refrigeration coils, various mounting and support brackets, and other mechanical obstructions. Because of the various obstructions and the general design of the drain trough, liquid runoff and debris from product are trapped from being rinsed down the waste drain. Consequently over a period of time the runoff solution combines with trapped debris and the debris begins to decay. Over a period of time the decaying debris creates an unpleasant odor not to mention unhealthy levels of harmful bacteria.
What is needed, therefore, are systems and methods for controlling contaminants (bacteria, mold, yeast spores, microorganisms, and so forth) in refrigerated and non-refrigerated display cases typically found in grocery stores. What is needed are display cases with improved sanitation.